Precision machine vision inspection systems (or “vision systems” for short) can be utilized to obtain precise dimensional measurements of inspected objects and to inspect various other object characteristics. Such systems may include a computer, a camera and optical system, and a precision stage that is movable in multiple directions so as to allow the camera to scan the features of a workpiece that is being inspected. One exemplary prior art system that is commercially available is the QUICK VISION® series of PC-based vision systems and QVPAK® software available from Mitutoyo America Corporation (MAC), located in Aurora, Ill. The features and operation of the QUICK VISION® series of vision systems and the QVPAK® software are generally described, for example, in the QVPAK 3D CNC Vision Measuring Machine User's Guide, published January 2003, and the QVPAK 3D CNC Vision Measuring Machine Operation Guide, published September 1996, each of which is hereby incorporated by reference in their entirety. This product, as exemplified by the QV-302 Pro model, for example, is able to use a microscope-type optical system to provide images of a workpiece at various magnifications, and move the stage as necessary to traverse the workpiece surface beyond the limits of any single video image. A single video image typically encompasses only a portion of the workpiece being observed or inspected, given the desired magnification, measurement resolution, and physical size limitations of such systems.
Machine vision inspection systems generally utilize automated video inspection. U.S. Pat. No. 6,542,180 teaches various aspects of such automated video inspection and is incorporated herein by reference in its entirety. As taught in the '180 patent, automated video inspection metrology instruments generally have a programming capability that allows an automatic inspection event sequence to be defined by the user for each particular workpiece configuration. This can be implemented by text-based programming, for example, or through a recording mode which progressively “learns” the inspection event sequence by storing a sequence of machine control instructions corresponding to a sequence of inspection operations performed by a user with the aid of a graphical user interface, or through a combination of both methods. Such a recording mode is often referred to as “learn mode” or “training mode.” Once the inspection event sequence is defined in “learn mode,” such a sequence can then be used to automatically acquire (and additionally analyze or inspect) images of a workpiece during “run mode.”
Video tools (or “tools” for short) and other graphical user interface features may be used manually to accomplish manual inspection and/or machine control operations (in “manual mode”). Their set-up parameters and operation can also be recorded during learn mode, in order to create automatic inspection programs, or “part programs.” Video tools may include, for example, edge/boundary detection tools, autofocus tools, shape or pattern matching tools, dimension measuring tools, and the like. Other graphical user interface features may include dialog boxes related to data analysis, step and repeat loop programming, and the like. For example, such tools are routinely used in a variety of commercially available machine vision inspection systems, such as the QUICK VISION® series of vision systems and the associated QVPAK® software, discussed above.
The machine control instructions including the specific inspection event sequence (i.e., how to acquire each image and how to analyze/inspect each acquired image) are generally stored as a “part program” or “workpiece program” that is specific to the particular workpiece configuration. For example, a part program defines how to acquire each image, such as how to position the camera relative to the workpiece, at what lighting level, at what magnification level, etc. Further, the part program defines how to analyze/inspect an acquired image, for example, by using one or more video tools such as edge/boundary detection video tools.
Editing a part program for a machine vision inspection system is a more complex task than editing a program for a machine tool or assembly robot or the like. For example, part programs for machine vision inspection systems include later portions that control operations and/or provide image-dependent measurement results that depend at least partially on the results determined by the execution of a previous portion of the program and/or on the particular instance of a workpiece that is being used to provide the images that are essential to the inspection operations. Furthermore, the required lighting and/or exposure time required for a particular image may depend on a particular instance of a workpiece. Furthermore, if a user saves a partially completed part program and recalls the part program at a later time to alter or finish the programming, it may be unknown if certain types of changes have occurred in the interim (e.g., changes in environmental conditions, the part being inadvertently moved on the stage, etc.) that may adversely affect the continuing edits to the part program. Due to such concerns, it has been a standard practice for some such systems to actually execute all of the instructions of a part program from the beginning, up to, and including any potential additional modifications or additions to the part program instructions, in order to verify that the modifications and/or additions are being programmed based on a realistic set of conditions for their operation. However, the execution of all of the instructions of a part program to provide a realistic operating condition for modifications or additions to the instructions is impractical for a large part program (e.g., those including a large number of image acquisitions, and/or feature inspections), which is particularly common for machine vision inspection systems that provide microscopic inspection (e.g., micron resolution measurements) on macroscopic objects (e.g., objects spanning tens or hundreds of millimeters). A need exists for an editing environment that can reliably update operating conditions in a short time (e.g., nearly “real time”) during editing operations and to allow more rapid, efficient, intuitive, and flexible and robust creation and editing of part programs for precision machine vision inspection systems.